In a medium sized pot, heat your butter, then add your onions.
Once they've browned, add your spices.
Now add your pumpkin puree, stir for about a minute or so.
Reduce the heat to low, add in your condensed milk and stir for about 5 minutes
Now add in your cheese and brown sugar, stir and allow to simmer for about 10 minutes. Make sure your heat isn't too hot, you don't want the sauce to become grainy.
Prepare the ravioli per the instructions on the package, or fill a (separate) pot with water, bring it to boil, add the ravioli, and then cook for about 5 to 6 minutes.
Once the ravioli is ready you can add it to the sauce or serve the sauce over it. Enjoy!